The invention concerns a rotary valve for control of a cylinder charge change of an internal combustion engine containing a plurality of combustion chambers, whereby two fresh gas or exhaust gas ducts, associated in each case with adjacent combustion chambers, for the purpose of connection with a fresh gas and, respectively, exhaust gas opening in the rotary valve, extend as regards their region in a common cross-sectional plane of the rotary valve.
In a rotary valve of like construction known from DE-OS No. 3,241,723, the exhaust gas ducts associated with adjacent cylinders have regions which extend in a cross-sectional plane located between the cylinders and which are provided with angularly offset mouth points on the periphery of the rotary valve. Depending on the prevailing angular position of the rotary valve, no mouth point or one mouth point will be located below the exhaust gas opening common to both exhaust gas ducts in the rotary valve housing. The exhaust gas opening is in communication with a known exhaust gas system of the internal combustion engine. Taking into account in particular the fact that ducts for fresh gas delivery must also be accommodated in the rotary valve, the course of the exhaust gas ducts and the position of the aforementioned mouth points in a common cross-sectional plane as described offer advantages regarding the attainment of a short axial dimension of the rotary valve.
On the other hand, the aforedescribed configuration of the rotary valve requires a relatively large diameter thereof inasmuch as the flow cross sections of the exhaust gas ducts in the rotary valve cannot be rendered indefinitely small. A large rotary valve diameter, however, suffers from the shortcoming that it results in a high sliding speed of the seals sliding on the valve periphery so that friction, frictional heat, wear and the driving torque of the cylindrical slide valve likewise become relatively large. Moreover, attention must be paid to a defined gap volume between the rotary valve and its housing as well as to sufficient heat transmission surfaces in the ducts.